Hydraulic machine



Sept. 27, I1966 s. D. HouGH 3,274,900

HYDRAULIC MACHINE FledAprl 5, 1964 i 12 Sheets-Sheet 1 SIDNEY DHVID HOUGR B7 Www/MW M04 W www,

Sept. 27, 1966 Filed April 5. 1964 "11s. D. HOUGH HYDRAULIC MACHINE l2 Sheets-Sheet 2 ll i 58 W l l lill l N VENTO? Elf- SIDNEY DHVID HOUGH Sept. 27, 1966 s. D. HoUGH 3,274,900

HYDRAULIC MACHINE Filed April 3, 1964 l2 Sheets-Sheet 3 g/fl Sept. 27, 1966 Filed April I5, 1964 s. D. HoUGH 3,274,900

HYDRAULIC MACHINE 12 Sheets-Sheet 4 Sept. 27, 1966 s. D, HOUGH HYDRAULIC MACHINE Filed April s, 1964 l2 Sheets-Sheet 5 Sept. 27, 1966 s. D. HOUGH HYDRAULIC MACHINE 12 Sheets-Sheet 6 Filed April 5. 1964 a u a o 'prune Sept. 27, 1956 s, D, HOUGH 3,274,900

HYDRAULI C MACHINE Filed April 5, 1964 l2 Sheets-5h68?, '7

1I mi Sept- 27, 196e s. D. HOUGH 3,274,900

HYDRAULI C MACHINE Sept. 27, 1966 s. D. HQUGH HYDRAULIC MACHINE Filed April 5, 1964 12 Sheets-Sheet 9 /32lll095765432/ Sept. 27, 1966 s D` HOUGH 3,274,900

HYDRAULIC MACHINE Filed April 5, 1964 12 Sheets-Sheet. 10

MORE THANNRMAL MAX/MUMSUCT/ONL/FI NVENTOR Y SIDNEY DDvrD HDL/@H Sept. 27, 1966 s. D. HOUGH 3,274,900

HYDRAULIC MACHINE Filed April 5, 1964 l2 Sheets-Sheet. 11

DISTANCE 7U0 FAR FOR NORMAL 511C 7'/0N SIDNE D VID HOUGH Sept. 27, 1956 s. D. HOUGH 3,274,900

HYDRAULIC MACHINE Filed April s, 1964 12 sheets-sheet 12 ILP United States Patent O HYDRAULIC MACHINE Sidney David Hough, 42 Leicester Ave., Glen Waverley, Victoria, Australia Filed Apr. 3, 1964, Ser. No. 357,238 Claims priority, application Australia, Apr. 4, 1963,

9 Claims. (Cl. 91-298) This invention relates to reciprocatory pumps and motors of the type which are driven by means of pressure uid.

There are known pumps and motors of this type which comprise a pair of reciprocatory elements, each of which acts as a valve for controlling the reciprocating motion of the other. One of the elements may be dwarfed and act solely as a valve or control piston. For example, the 'high pressure hydraulic pump disclosed in Australian patent specification No. 133,465 and the hydraulic motor described in Australian p-atent specication No. 154,502 each has a single working piston and a dwarfed piston which acts solely as a control valve. Alternatively, both elements may comprise working pistons as in the pump described in Australian patent specification No. 158,925. However, in all of these known pumps `and motors the two reciprocatory elements are located in separate bores in a body part, which bores `are interconnected at selected positions, by cross-drilled passages in the body part. This arrangement leads to complexity in the layout of interconnecting passages `and great diculty in machining in the cross-drilling of the passages. Furthermore, pumps constructed in this manner are not compact and are therefore not suitable for pumping lluid from small diameter boreholes, Wells and the like. It is an object of this invention to provide a pump or motor of the type referred to in which the necessity for cross-drilling `of the passages is substantially reduced. A further object is to provide a construction which can readily be tted into small diameter spaces.

It is a further object of this invention to provide a pump which can be readily adapted either to discharge fluid at a greater rate lthan the rate of uid injection but at a lower pressure than the injection pressure, the `additional fluid being sucked into the pump from a source from which uid is to be pumped `or alternatively, to discharge some of the iluid injected thereinto at 4a greater pressure than the injection pressure, the remainder of the uid being discharged separately at low pressure. A pump which may be so adapted gives advantages which will become apparent from the ensuing description of an exemplary construction and several exemplary uses of such a pump.

According to the invention I provide a hydraulic machine of the type driven by means of pressure lluid and comprising a pair of reciprocatory elements each of which serves `as a valve for controlling the reciprocating motion `of the other, comprising a plurality Iof bores slidably carrying said reciprocatory elements, a plurality of ducts spaced circumferentially around the bores and extending longitudinally thereof, said bores being provided at predetermined axial and circumferential positions with ports each of which communicates with a duct according to its circumferential position.

In explaining this invention it is proposed to discuss by way of illustration three forms of pump. In all of these forms of pump the pump casing is formed with longitudinally extending passageways which serve as ducts either to convey fluid -to and from the pump or as transfer ducts to connect various chambers within the pump with the ducts which convey fluid to and from the pump. In the constructions to be described the casings ice are formed more or less symmetrically with a number of equally spaced passageways arranged about the periphery of the pump casing. In some cases a number of these passageways 'are -combined t-o form a single duct and in others :a single passageway only acts as a duct. Throughout .the ensuing description however the term duct will be used when discussing the function of the apparatus even Ialthough in some cases the duct referred to comprises only a single passageway.

The construction of the three forms `of pump which will be discussed, land their manner of operation, are illustrated in the accompanying drawings in which:

FIGURE 1 is a plan view of a tirst form of pump which has been constructed according .to the invention;

FIGURE 2 is -a cross-section on the line 2-2 in FIGURE l;

FIGURE 43 is an underneath view lof the pump shown in FIGURES 1 and 2;

FIGURE 4 is a cross-section on the line 4 4 in FIG- URE 2;

FIGURE 5 is a cross-section on the line 5-5 in FIG- URE 2;

FIGURE 6 is a development of the sleeve 25 shown in FIGURE 2;

FIGURE 7 is an exploded perspective view of one of the cylinder walls within the pump which illustrates the construction of ports which lare provided therein;

FIGURE 8 is a plan view of a spacer which is incorporated in the pump and is numbered 42 in FIG- URE 2;

FIGURE 9 is a perspective view on the line 9-9 in FIGURE 8;

FIGURE 10 is a plan view of a furtherl spacer which is incorporated in the pump and is numbered 44 in FIGURE 2;

FIGURE 11 is a perspective view on the line 11-11 in FIGURE 10;

FIGURE 12 is a cross-section on the line 12-12 in FIGURE 2;

FIGURE 13 is a cross-section on the line 13--13 in FIGURE 2;

FIGURE 14 is a cross-section on the line 14,-14 in FIGURE 2;

FIGURE 15 is a cross-section `on the line 15-15 in FIGURE 2;

FIGURE 16 is a cross-section on the line 16-16 in FIGURE 2 when the distribution valve piston 48 is at its upper extremity of travel rather than at its lower extremity of travel las shown in FIGURE 2;

FIGURE 17 is a cross-section on the line 17-17 in FIGURE 2 when the distribution valve piston 48 is at its upper extremity `of travel rather than `at its lower extremity of travel as shown in FIGURE 2;

FIGURE 18 is a cross-section on the line 18-13 1n FIGURE 2;

FIGURE 19 is a cross-section on the line 19--19 in FIGURE 2;

FIGURE 20 is a cross-section on the line 20-20 in FIGURE 2;

FIGURE 21 is a cross-section on the line y21-21 in FIGURE 2;

FIGURE 22 is a cross-section on the line 22-22 in FIGURE 2 when the compound piston assembly denoted generally as 45 is at its upper extremity of travel rather than at its lower extremity of travel as shown in FIG- URE 2;

FIGURE 23 is a cross-section on the line 23-23 in FIGURE 2 when the compound piston assembly denoted generally as 45 is at its upper extremity ofI travel rather than at its lower extremity `of travel as shown in FIG- URE 2;

FIGURES 24 to 30 illustrate diagrammatically the pump shown in FIGURES 1 to 23 at various stages of its complete cycle of operation;

FIGURE 31 is a cross-sectional view of a second form of pump constructed according to the invention;

FIGURE 32 is a cross-sectional view of a third form of pump constructed according to the invention;

FIGURE 33 is a cross-section on the line 33-33 in FIGURE 32;

FIGURES 34, 35, and 36 diagrammatically represent the pump illustrated in FIGURES 32, 33 connected for operation in three `different manners;

FIGURES 37, 38, and 39 diagrammatically represent connections to the upper end of the pump shown in FIGURES 32, 33 corresponding to the connections shown in FIGURES 34, 35 and 36 respectively;

FIGURES 40, 41 and 42 diagrammatically represent connections to the lower end of the pump shown in FIG- URES 32, 33 corresponding to the connections shown in FIGURES 34, 35 and 36 respectively;

FIGURE 43 is a. development of the sleeve 161 shown in FIGURE 32;

FIGURE 44 diagrammatically represents the lower part of a pump of the form illustrated in FIGURE 31, to which an additional pumping element has been added;

FIGURE 45 Vdiagrammatically represents the lower part of a pump of the form illustrated in FIGURE 31, to which two additional pumping elements have been added;

FIGURES 46 to 55 show a pump used in various manners.

The pump illustrated in FIGURES 1 to 23, comprises a pumping chamber assembly 19 having an outer casing 21 and a distribution valve chamber assembly 20 having an outer casing 22 which are separated by a gasket 23. As shown in FIGURES 4 and 5 `and 12 to 23 each of the outer casings 21, 22 is provided with thirteen internal tins 18 which project radially inwards and extend along the length thereof. Sleeves 24, 25 tit within the outer casings 2l, 22 respectively so that two jackets, each of which is divided into thirteen clrcumferentially spaced and longitudinally extending passageways are formed. As shown in FIGURE 2 the gasket 23 is formed with openings to establish communication between longitudinally aligned passageways in the two jackets so that the passageways extend throughout the lengths of both jackets.

A tubular insert 26 is located within sleeve 25 by means of a Spacer '27, A distribution valve piston 28 is slidably mounted within `the insert 26 and is provided with two circumferential grooves 29, 30 which are positioned to co-act in a manner to be hereinatfer described, with ports or slots cut in the sleeve 25, spacer 27 and insert 26 to establish and cut olf communication between selected passageways in the jacket according to the position of the distribution valve piston.

The upper end of the distribution valve jacket is closed by an end cap 31 which is provided with a delivery pipe 32 and an injection pipe 33. Delivery pipe 32 communicates with three of the passageways via port 34. These three passageways are thereby combined to act as a single duct D. Injection pipe 33 communica-tes with :another three of the passageways via port 35 and these three passageways are thereby combined to act as a single duct I.

The lower end of the pumping chamber jacket is closed by a further end cap 36 which is provided with a suction pipe 37. This latter pipe communica-tes with three of the passageways via port 38. These three passageways are thereby combined to act as a single duct S.

Two tubular inserts 39, 4@ are provided, one within each end of the sleeve 24 of the pumping chamber, and are located by spacers 41, 42 and 43, 44. As shown in FIGURES 8 to 1l, spacers 42 and 44 are themselves complex structures provided with ports, the yfunction of which will be hereinafter explained. A compound piston assembly denoted generally as 45 is slidably mounted at its middle section within the sleeve 24 and at its ends within the tubular inserts 39, 40. The piston assembly 45 comprises two opposing high pressure pistons 46, 47 which are separated by what is effectively a larger diameter, double ended, low pressure piston which is formed by two spaced end pistons 48, 49. The end pieces 48, 49 are provi-ded with ports 56, 51 which are normally closed by spring loaded non-return Valves 52, 53. The two smaller diameter high pressure pistons 46, 47 are provided with circumferential grooves 54, and 56, 57. Spring loaded non-return valves 58, 59 are fitted to the spacers 42, 44 so that chambers 62, 63 are formed between those valves and the end pieces 48, 49.

Duct S is in constant communication with the chamber 60 between the end pieces 48, 49 via slot 61 in the sleeve 24. Chamber 62A between spacer 41 and end piece 48, and chamber 63A between spacer 43 and end piece 49, are in constant communication with delivery duct D via slots 64, 65 which are cut in sleeve 24. Chamber 66 at the end of the high pressure piston 47 is, by means of a port 67 which passes through insert 40, spacer 43 and sleeve 24, in constant communication 'with one of the passageways, which passageway acts as a duct 68 (see FIGURE 21). Chamber 69 at the end of the high pressure piston 46 is, by means of a port 70 through insert 39, spacer 41 and sleeve 24, in constant communication with a passageway which acts as a duct 71 (see FIGURE 18). Chamber 72 at the upper end of the distribution valve piston 28 is, by means of a port 73 through sleeve 25, spacer 27 and insert 26, in constant communication with one of the passageways which acts as duct 74 (see FIGURE 12). Chamber 75 at the lower end of the distribution valve piston is, by means of a port 76 through the sleeve 25, spacer 27 and insert 26, in constant communication with the passageway or duct 77 (see FIGURE 15). A series of ports is provided in sleeve 25, spacer 27 and insert 26 and also in sleeve 24, spacers 42, 44 and inserts 39, 40 to co-act with the circumferential grooves in the distribution valve piston and the compound piston assembly such that communication between selected ducts in the jackets is established and cut off according to the positions of these two pistons in such a manner that cach of these two pistons reciprocates automatically between upper and lower positions. Thus, when the distribution valve piston 2S is in its lower position as shown in FIGURE 2, the groove 29 connects a pair of ports 78, '79 through the sleeve 25, spacer 27 and insert 26 to establish communication between ducts J and 68 (see FIGURE 13) and the groove 30 connects a similar pair of ports 80, 81 to establish communication between ducts 71 and D. (See FIGURE 14.) When the distribution valve is in its upper position, the groove 29 connects a pair of ports 82, 83 to establish communication between ducts 68 and D (see FIGURE 16) and the groove 30 connects a `pair of ports 84, 35 to establish communication between ducts J and 71 (see FIGURE 17). When the compound piston assembly 45 is in its lower position as shown in FIGURE 2, the groove 54 connects a pair of ports 86, 87 through sleeve 24, spacer 42 and insert 39 to establish communication between ducts I and 74 (see FIGURE 19) and the groove 56 connects a pair of ports 88, 89 through sleeve 24, spacer 44 and insert 40 to establish communication between ducts 77 and D (see FIGURE 20). When the compound piston assembly 45 is in its upper position, the groove 55 connects 'a pair of ports 90, 91 through the sleeve 24, spacer 42 and insert 39 to establish communication between ducts 74 and D (see FIGURE 22), and the groove 57 connects a pair of ports 92, 93 through sleeve 24, spacer 44 and insert 48 to establish communication between ducts J and 77 (see FIGURE 23).

In order to provide a pump of minimum longitudinal dimensions it is desirable that the aforesaid ports be of minimum longitudinal depth immediately adjacent the pistons. To this end the inserts 26, 39 and 4t) are provided with a series of circumferentially extending slots similar to those shown in FIGURE 7 which comprise the innermost extremities of those ports. However, the Outer extremities of the ports, being in communication with the longitudinally extending passageways, preferably extend longitudinally. Therefore these outer extremities of the ports consist of a series of vertically extending slots, similar to those shown in FIGURE 7, cut in the sleeves 24 and 25. The circumferentially and vertically extending slots are connected by holes drilled in the spacers 27, 41, 42, 43 and 44. In the pairs of ports which coact with the grooves in the various pistons, the holes through the spacers are drilled tangentially to the inside peripheral surface thereof. This method of drilling enables the length of the slots in the inserts to be adequately covered by the drilled holes and also facilitates a smooth flow of fluid through the circumferential grooves and the ports.

As mentioned above the interaction between the ports and the circumferential grooves in the various pistons establishes and cuts off communication between selected ducts in the jackets in such a manner that the pistons reciprocate automatically between upper and lower posi tions.

The operation of the pump will now be described and reference `will be made to FIGURES 24 to 3() which illustrate diagrammatically the pump at various stages of its complete cycle of operation.

The pump is operated by injecting pressure iluid into the injection pipe 33 and therefore into the duct I and connecting the suction pipe 37 and therefore the suction duct S to a source of fluid to be pumped. Throughout FIGURES 24 to 30 the passage of fluid at injection pressure is represented by full line arrows, the passage 0f fluid at suction pressure by dot and dash arrows, and the passage of fluid at discharge pressure by dotted arrows. At the start of a cycle of operation the compound piston assembly 45 and the distribution valve piston 23, are both at the lower limit of their travel (see FIGURE 24). When the pump is in this condition duct I communicates with duct 68 through ports 76, 79 which are connected by circumferential groove 29 (FIGURE I3). Thus high pressure iluid is directed through port 67 into chamber 66 (FIGURE 21). The duct I also communicates with duct 74 through ports 36, 87 which are connected by circumferential groove 54 (FIGURE 19). High pressure iluid is therefore also directed through port 73 into the chamber 72 (FIGURE l2). Chamber 75 and duct 77 communicate with duct D via ports 38, 89 lwhich are connected by circumferential groove 56 (FIGURE 20). The chamber 69 communicates with delivery duct D through duct 71, ports 80, SI and circumferential groove 30 (FIGURE 14). The high `pressure fluid injected into chamber 66 causes the piston assembly 45 to rise. As shown in FIGURE this movement of the piston assembly 45 immediately disconnects chamber 75 from duct D, and also chamber 72 from the high pressure fluid duct J so that chambers 72 and 75 are effectively sealed. The distribution valve piston 23 is therefore locked against movement from its lowermost position. As the piston assembly 45 rises, fluid is displaced by the piston 48 through valve 52 and slot 64 in the sleeve 24 to the delivery duct D (FIGURE 4). Fluid is also expelled from the chamber 69 and duct 71 into delivery duct D via ports 80, @I which are connected by the circumferential groove (FIGURE 14). The upward movement of the compound piston assembly 45 also creates a drop in pressure in chamber 63 which draws in lluid from duct S via the slot 61, chamber 60 and non-return valve 53. As the compound piston assembly 45 approaches the upper limit of its travel (see FIGURE 26) circumferential groove 57 connects ports 92, 93 which establishes communication between the in'ection iluid duct I and duct 77 (see FIGURE 23) causing high pressure fluid to flow into chamber 75 (FIGURE 15 At the same time circumferential groove 55 connects ports 90, 91 see FIGURE 22) allowing fluid to be exhausted from chamber '72 and duct 74, into delivery duct D. The distribution valve piston 28 now starts to move upwardly. The upward movement of circumferential grooves 29, 3i) cuts off communication between the injection duct I and the chamber 66 and also the communication between chamber 69 and delivery duct D (see FIGURE 27). Chambers 66 and 69 are thereby effectively sealed so that the compound piston assembly is locked at its highest limit of travel.

The compound piston assembly 45 remains locked in this position until the distribution valve piston 28 approaches its upper limit of travel. At this stage (see FIGURE 28) the circumferential groove 36 is aligned with ports S4, 35 (FIGURE 17) to establish communication between the injection duct I and the duct 71 whereby high pressure fluid is directed into chamber 69. At the same time circumferential groove 29 connects ports 82, 83 (see FIGURE 16) allowing the iluid in the duct 68 and the chamber 66 to be exhausted into the delivery duct D. Thus the compound piston assembly 45 begins a return stroke. As soon as the compound piston assembly 45 begins its return stroke (see FIGURE 29) circunn ferential grooves and 57 are moved so that duct 74 and chamber 72 are sealed with fluid at discharge pressure and duct 77 and chamber 75 are sealed with high pressure fluid. The distribution valve piston therefore remains locked at its upper extremity of travel while the compound piston assembly 45 completes its return stroke. During this return stroke fluid is pumped. by piston 49 from the chamber 63 via the one-way valve 59 and slot in the sleeve 24 into the delivery duct D. A decrease in pressure is created in chamber 62 which draws in fluid from duct S, via slot 6I, chamber 6@ and one'way valve 52. As the compound piston assembly 45 approaches the end of its return stroke (see FIGURE 30) the circumferential groove 54 is aligned with ports 66, 87 to establish communication between the injection duct I and the duct 74 (FIGURE 19) so that high pressure fluid is directed to chamber 72. At the same time cir cumferential groove 56 connects ports 88, 89 (FIGURE 20) to allow the lluid in chamber 75 and duct 77 to exhaust to the delivery duct D. The distribution valve piston 28 therefore commences a return stroke and in doing so causes the chambers 69 and 66 to be sealed so that the compound piston assembly 45 remains at the lower limit of its travel while the distribution valve piston completes its return stroke whereupon the cycle of operation is complete. A compression spring 94 returns the distribution valve piston to the lower extremity of its travel when the injection of pressure fluid is stopped so that the pump cannot stop in a jammed condition.

The distribution valve piston 28 is provided at each end with bleeder holes 95, 96 which connect respectively grooves 29 and 30 with chambers 72 and 75. These bleeds serve to maintain the pressure at the ends of the distribution valve piston at the stages in the cycle in which the piston should be locked at one or other end of its stroke. The bleed 96 serves also to permit the escape of fluid from chamber when the pump is shut off and thereby permits the piston to return to its lowermost position under the influence of the spring 94 irrespective 0f the position of the compound piston assembly 45.

From the above description of a cycle of operation of the pump it will be appreciated that injection of high pressure fluid into the duct I will cause the compound piston assembly and the distribution valve piston to reciprocate automatically. During each stroke of the compound piston assembly 45, fluid is ejected into the deliv* ery duct D by one of the low pressure pistons 48, 49 and one of the high pressure pistons 46, 47 so that the amount of fluid ejected is equal to the swept volume of the low pressure pistons 48, 49. The pressure of the fluid discharged will depend upon the ratio between the area of the low pressure pistons 48, 49 and the area of the high pressure pistons 46, 47. This ratio can be changed by inserting a liner within that part of the sleeve 24 which is swept by the -low pressure pistons and using smaller diameter low pressure pistons. This reduces the swept volume in the chambers 62, 63 and also the total thrust exerted on the low pressure pistons.

The above described pump is designed kto receive an injection o-f relatively high pressure uid and deliver a larger quantity of fluid at a lower pressure. By providing an extra set of circumferential grooves in the distribution valve piston and rearranging the hydraulic circuit so that the Aflow of fluid to and from `the pumping chambers swept by the low pressure Ipiston is controlled by that extra set of circumferential grooves, the non-return valves may be dispensed with. Furthermore a pump modied in this manner may be operated in similar fashion to the above described pump, or, by a simple change in connections, may readily tbe adapted to receive an injection of relatively low pressure `fluid and discharge some of this huid at a higher pressure. Two pumps of this kind yare illustrated in FIGURE 3l and FIGURES 32 to 43 respectively. The construction and operation of `these two pumps is substantially identical except that in `the pump illustrated in FIGURES 32 to 43, a pumping piston has been added to the distribution valve piston and a Ifurther set `of circumferential `grooves has been ladded to the -other piston to control the flow of iluid to and from this pumping piston whereby the pump cornprises ltwo identical compound piston assemblies each 'functioning as the control piston for the other. `In this pump outer casings 97, 98, 99, 100 and sleeves 101, `102, 103, 104 are abutted end to end against gaskets 105, 106, 107. Each of the outer casings is so provided with internal radial ns 108, and each of the gaskets are so formed that thirteen circumferentially spaced ducts extend throughout the length of the jacket formed by the outer casings and outer sleeves. These ducts are numbered 1 to 13 inclusive. End caps 109, 110 close each end of all of the ducts except ducts 1, 2 and 3 which therefore form a single duct Z, duct 6 which will hereinafter be referred to Ias duct X, and cut 11 which will hereinafter be referred to as duct Y.

Inner sleeves 111, 112, 113, 114 are located within outer sleeves 101, 102, 103 and 104 respectively by means of spacers 115, 116, 117, 118.

The pump is provided with two identical compound piston assemblies 119, 120. The two compound piston assemblies, together with the clylindrical walls form chambers A, B, C, D, E, F, G and H. The cylinder walls Iswept by the pistons (four of which are comprised of sleeve a spacer and an inner sleeve, and two of which are formed by sleeves only) are slotted according to the code set out beside each of FIGURES 34, and 36 which diagrammatically represent the pump connected for operation in three different manners. A pair of ports pass one through each end of inner sleeve 111, spacer 115 and outer sleeve `101, such that chamber A 4is in constant communication with duct 12 and chamber B is in constant communication with duct 7. Chamber C is in constant communication with duct 4 via a slot in sleeve 102. A port passing through inner sleeve 112, spacer 116 and outer sleeve 102 establishes constant communication between chamber D and duct 9. A pair of ports pass one through each end of inner sleeve 113, spacer 117 and outer sleeve 103 to establish constant communication between chamber E and duct 10 and between chamber F and duct 5. Chamber G is in constant communication with duct 8 via slot pas-sing through outer sleeve 104 and chamber H is in constant communication with duct 13 via a port which passes through inner sleeve 114, spacer 118 and outer sleeve 104.

In addition to the ports which establish constant communication between chamber A and duct 12 and between chamber B and duct 7, the cylinder wall which is comprised of inner sleeve 111, spacer and outer sleeve 101 is further provided at each of eight axial spacings with a pair of ports which when they are connected by a circumferential groove in the compound piston assembly 119 establish communication between selected ducts. Thus at one axial spacing there is a port to duct Y (i.e. duct 11) and a port to duct 8 (and thus to chamber G). At the next adjacent axial spacing there is a port to individual duct 1 of the combined duct Z and also a port to duct 8 and therefore to chamber G. At the next axial spacing one port goes to individual duct 3 of the combined duct Z and the other port goes to duct 10 and therefore to chamber E. The positions of the remaining ports will now be apparent from the code set out beside each of FIGURES 34, 35 and 36. Each of the ports passing through the sleeves, inserts and spacers of this pump are formed in similar fashion to those of the previously described pump which are particularly illustrated in FIGURES 12 to 23. 'The arrangement of the ports is further demonstrated by FIGURE 43 which is a develop-ment of outer sleeve 101. The positions of the slots as illustrated in this figure can readily be correlated with the code by means `of the numerals which are spaced along the upper edge of the developed sleeve to represent the circumferential locations ofthe ducts 1 to 13.

Outer sleeves 101 and 103 are identical, one being merely turned end to end to the other before assembly of the pump. Similarly sleeves 102 and 104 are also identical.

As mentioned above, FIGURES 34, 35 and 36 diagrammatic-ally illus-trate the pump connected for operation in three different manners. For Ithe operation shown in FIGURE 34 duct Y is connec-ted via a foot valve to 4a source from which fluid is to be pumped (all ducts and por-ts transmitting fluid at source pressure being represented by dot and dash lines), duct X is connected to a source of high pressure uid (all ducts and ports transmitting this high pressure uid being represented by full lines) and duct Z is connected to discharge (all ducts and ports transmitting uid at discharge pressure being represented by dotted lines). These connections may be made as shown in FIGURES 37, 40 in which duct Y is plugged at the upper end cap 109 and ducts X and Z are plugged at the lower end cap 110. The operative connections of the ducts X and Z are then made at the upper end cap 109 and the operative connection for duct Y in the lower end cap 110. However, any of the duct connections could be reversed. The pump then operates in similar fashion to the pump described above with reference to FIGURES l to 30. The pump receives high pressure fluid through duct X and discharges a greater quantity of lower pressure Huid from duct Z. The cycle of operation is somewhat similar to that of the rst described pump as illustrated in FIGURES 24 to 30. Thus, at the start of a cycle of operation, both compound piston assemblies 119 and 120' are each at their lowermost positions as shown in FIGURE 34.

Compound piston 120 moves through an upward stroke while piston -assembly 119 remains locked at its lowermost position. At the completion of the upward stroke of piston assembly 120, piston assembly 119 commences an upward stroke while piston assembly 120 remains locked at its uppenmost position. When piston assembly 119 reaches i-ts uppermost position, piston assembly 120 is driven through a return stroke and at the completion thereof, piston assembly 119 follows in similar fashion whereupon the cycle `is complete. When operated in this way the pump may be used for the following purposes:

(a) To assist in the siting of a conventional pump or power unit remotely from the source from which Huid is to be pumped where this is more convenient. Such uses are illustrated in FIGURES 46, 47, 48 and 49. In

FIGURES 47 and 49 a regulating valve is denoted by the letter R.

(b) For use as additional equipment to a conventional pump in a circulatory system to enable the conventional pump lto raise fluid at a lesser tra-te than its normal capacity to a higher level than its nominal capacity head. This type of operation is illustrated in FIGURE 50.

(c) To raise water from shallow excavations, sumps, pits, etc. by `using Waiter at mains pressure as the injection fluid. Thus a pump having @a piston ratio of say 3:1 will, on the injection of water from a mains supply, raise water to slightly less .than Va of the available head pressure in the mains at a rate which is twice `the irate of llow f mains pressure water into the pump (i.e. for every single unit of fluid injected into ythe pump three units are discharged). A pump having a piston ratio of say 4:1 will, on injection -of water at mains pressure, raise water to slightly less than 1A of the height of the available head pressure at `a rate which is three times greater than the nate of injection of water into the pump. Use of the pump in this [manner illustrated in FIGURE 5l. When necessary a booster pump can be inserted between the supply ytap and one or more pumps according to the invention to increase the discharge and delivery head as required.

(d) To change the suction lift of the conventional pumlp to a suction head and/ or lto increase the height of the suction head 0f .the `conventional pump to more than that obtained by atmospheric pressure (see FIG- URE 52). The letter R denotes a regulating valve.

For the operation shown in FIGURE 35 duct X is connected via a foot valve to a source from which uid is to be pumped (all ducts and ports transmitting Huid at source pressure being represented by do-t and dash lines). Duct Y is connected to a source of pressure fluid (all ducts and ports `transmitting liuid at this pressure being represented by full lines) and duct Z is again connected to discharge (see dot and dash lines). Typical connections in this manner are shown in FIGURES 38, 41. In this case the piston assemblies 119, 120 reciprocate as before but the injection fluid is now directed into the chambers swept by the larger pistons of the cornpound piston assemblies. During each stroke of a piston assembly the thrust is provided by fluid at injection pressure acting on one side of the larger piston of the assembly and fluid is forced into duct Z by the other side of the larger piston and also by one of the smaller pistons. Therefore the rate of discharge of fluid from the pump is only slightly greater than the rate of injection of lluid thereinto and -the discharge pressure is only slightly less than the injection pressure. The operation of `the pump in this manner is often more suitable for pumping water from deep wells and bore holes than the method of operation illustrated in FIGURE 34. For instance, to use a pump having a piston ratio of 3:1 in the manner illustrated in FIGURE 34 to raise fluid through a head of 100', injection fluid at a pressure head of 300 would be required. However, by using a similar pump with the connections shown in FIGURE 35 injection fluid a-t a head of only 100 X 37g would be required. This reduction in the required injection pressure is accompanied by a decrease in the discharge rate of the pump. However, in pumping fluid from deep bores the injection pressure which would be required if the lpump were operated according to the method illustrated in FIGURE 34 would often `be prohibitive. An example of a pump operating in the manner shown in FIGURE 35 to pump waterfrom a deep well or bore is illustrated in FIGURE 5 3 wherein the letter R denotes a regulating valve.

A third method of operation of the pump is shown in FIGURE 36 in which low pressure fluid is injected into duct Z (see dotted lines), duct X is the delivery duct (see full lines) and duct Y is a surplus discharge duct (see dot and dash lines). During each stroke of either of the compound pist-on assemblies, the thrust is provided by .the action of low pressure fluid on one of the small pistons and one side of the largeV piston of the assembly. Fluid is forced into duct X by the other small pist-on. Fluid -is also discharged by the large piston into duct Y. Thus, during operation of the pump in this manner fluid is dischanged from duct X at a greater pressure than, and at a lower rate than, thel uid injected into duct Z. The surplus tluid is discharged from duct Y at a pressure lower than the injection pressure. Examples of the use of the pump in this manner are illustrated in FIGURES 54 and 55. FIGURE 54 shows a pump hacing a 4:1 piston ratio receiving water from a plentiful source at a head of 20 and delivering approximately 1A of this Water to a tank at a height of 80', the surplus water being run off. FIGURE 55 shows a pump having a 4:1 piston ratio being used in a circulatory system to increase the delivery head of a conventional pump at the expense of discharge capacity.

By modifying the end caps 109 and 110, the iuid passing through the larger piston chambers B, C, F and G can be kept separate from the uid passing through the smaller piston chambers A, D, E and H so that there are two distinct hydraulic circuits through the pump. This may lbe achieved by constructing the end caps so as to permit the flow :of fluid to or from duct 1 through the Z duct connection in end cap 169 only and the flow of lluid to or from duct 3 through the Z duct connection in end cap 110 only. In this manne-r ducts 1 and 3 are separated from one another, and since duct 1 is connected through the distribution valve p-istons to the larger piston chambers only and duct 3 is conne-cted through the dist-ribution valve pistons to the smaller piston chambers only, two separate hydraulic circuits are formed. A pump modified in this manner may be used Ito pump liquids which must not be contaminated with the injection or motive fluid of the pump. One specic application for such a pump is in the pumping of inflammable liquids, where the presence of an electrically driven pump near the inammable liquid would create a lire hazard.

The pump shown in FIGURE 31 has a similar construction to that described above with reference to FIG- URES 32 to 43. By removing from the pumpshown in FIGURE 32 the lower part of piston assembly 119, the outer casing 98, sleeve 102, insert spacer 116, insert liner 112, two of the circumferential grooves in piston assembly and the ports in sleeve 103, which are associated with these latter grooves, the pump shown in FIGURE 31 may be obtained. This .pump operates in similar fashion to the one shown in FIGURE 32 but only one of the piston assemblies performs a pumping function, the other piston acting merely as a control valve.

FIGURES 44 and 45 illustrate a method of altering the ratio between the pressures of the injection and discharge uids which is particularly applicable to pump-s constructed as shown in FIGURES 31 and 32. FIG- URE 44 diagrammatically represents the lower part of a pump of the type shown in FIGURE 3l which has been modified by the insertion .of an additional or supplementary pump assembly which consists of an outer casing and outer sleeve, an inner sleeve with spacer, plus a compound piston and is denoted generally as 121. The supplementary piston assembly is provided with por-ts to connect the two extra pumping chambers to duct 8 and duct 5, and so establish constant communication between the chambers on the same side of the large pistons (Le. chambers on the same side of the large pistons are connected in parallel). Duets 10 and 13, being connected separately to the small piston chambers E and H, are unchanged by the insertion. In a pump having a ratio between larger and small piston areas of 3:1, the insertion of one supplementary pump assembly will increase the fluid pressure ratio to 5:1. Any number of supplementary piston assemblies may be inserted. FIG- URE 45 illustrates a pump as in FIGURE 44, but in which a second supplementary piston assembly 122. has been inserted.

I claim:

1. An hydraulic machine of the type driven by means of pressure fiuid and comprising a pair of reciprocatory elements each reciprocable in a bore and each serving as a valve to control the reciprocato-ry motion of the other; comprising a hollow cylindrical casing and a hollow cylindrical liner located with the casing and spaced therefrom and defining a bore, a plurality of longitudinally extending ribs extending between the casing and the liner to divide the space therebetween to form a plurality of longitudinally extending ducts, and a plurality of ports positioned at predetermined axial and circumferential positions with respect to the bores, each said port providing communication between the bore and a duct according to its circumferential position, wherein at least part of said liner is of complex structure and comprises an outer sleeve and an inner sleeve and a spacer therebetween.

2. An hydraulic machine as claimed in claim 1 wherein the outer sleeve extends throughout the length of said casing.

3. An hydraulic machine of the type driven by means of pressure fiuid and comprising a pair of Areciprocatory elements each reciprocable in a Ibore and each serving as a valve to control the reciprocatory motion of the other; comprising .a hollow cylindrical casing and a hollow cylindrical liner located Within the casing and spaced therefrom and defining a bore, a plurality of longitudinally extending ribs extending between the casing and the liner to divide the space therebetween to form a plurality of longitudinally extending ducts and a plurality of ports positioned at predetermined axial and circumferentail positions with respect to the bores, each said port providing communication between the bore and a duct according to its circumferential position, wherein at least part of said linear is lof complex structure and comprises an outer sleeve and an inner sleeve and an annular spacer therebetween and wherein at least some fof said ports comprise a hole extending through said spacer substantially tangentially to the inner peripheral surface thereof.

4. An hydraulic machine as claimed in claim 3 wherein said hole extends between an elongated slot in the outer sleeve and an elongated slot in the inner sleeve, said slots being arranged respectively longitudinally and Icircumferentially of said outer and inner sleeves.

5. A hydraulic machine of the type driven by means of pressure fluid and comprising a pair of reciprocatory elements each reciprocable in a bore and each serving as a valve to control the reciprocatory motion of the other;

comprising a hollow casing, a hollow liner located within the casing and spaced therefrom and defining a bore, a plurality of longitudinally extending ribs extending ribs extending between the casing and the liner to divide the space therebetween to form a plurality lof longitudinally extending ducts, and a plurality of ports positioned at predetermined axial and circumferential positions with respect to the bore, each said port providing communication between said -bore and a duct according to its circumferential position.

6. A hydrualic machine as claimed in claim 5, in which the said ribs are formed integrally with the casing whereby the casing is provided with a plurality of longitudinally extending and inwardly directed channels which are closed by the liner to form said longitudinally extending ducts.

A hydraulic machine of the type driven by means of pressure uid and comprising a pair of reciprocatory elements, each serving as ,a valve to control the reciprocatory motion of the other; comprising .a hollow casing, a hollow liner within the casing and spa-ced therefrom and defining a plurality of coaxial bores which slidaibly receive said reciprocatory elements, a plurality of longitudinally extending ribs extending between the casing and the liner to divide the space therebetween and thereby defining a plurality of ducts spaced around the bores and extending longitudinally thereof, and a plurality of ports positioned at predetermined axial and circumferential positions with respect to lsaid bores, each said port providing communication between a bore and a duct according to its circumferential position.

8. A hydraulic machine as claimed in claim 7, wherein at least part of said liner is of complex structure and comprises an outer sleeve and an inner sleeve and a spacer therebetween.

9. A hydraulic machine as claimed in claim 8, wherein said outer sleeve extends through the length of said casing.

References Cited by the Examiner UNITED STATES PATENTS 653,247 7/1900 Kimman 91-298 662,815 11/ 1900 Phillips 91-298 705,436 7/1902 Pecaro 91-298 2,348,243 5/1944 4Cole 91-298 3,0045 23 10/1961 Christensen 91-298 MARTIN P. SCHWADRON, Primary Examiner. PAUL E. MASLOUSKY, Assistant Examiner. 

1. AN HYDRAULIC MACHINE OF THE TYPE DRIVEN BY MEANS OF PRESSURE FLUID AND COMPRISING A PAIR OF RECIPROCATORY ELEMENTS EACH RECIPROCABLE IN A BORE AND EACH SERVING AS A VALVE TO CONTROL THE RECIPROCATORY MOTION OF THE OTHER; COMPRISING A HOLLOW CYLINDRICAL CASING AND A HOLLOW CYLINDRICAL LINER LOCATED WITH THE CASING AND SPACED THEREFROM AND DEFINING A BORE, A PLURALITY OF LONGITUDINALLY EXTENDING RIBS EXTENDING BETWEEN THE CASING AND THE LINER TO DIVIDE THE SPACE THEREB ETWEEN TO FORM A PLURALITY OF LONGITUDINALLY EXTENDING DUCTS, AND A PLURALITY OF PORTS POSITIONED AT PREDETERMINED AXIAL AND CIRCUMFERENTIAL POSITIONS WITH RESPECT TO THE BORES, EACH SAID PORT PROVIDING COMMUNICATION BETWEEN THE BORES AND A DUCT ACCORDING TO ITS CIRCUMFERENTIAL POSITION, WHEREIN AT LEAST PART OF SAID LINER IS OF COMPLEX STRUCTURE AND COMPRISES AN OUTER SLEEVE AND AN INNER SLEEVE AND A SPACER THEREBETWEEN. 